Lawinenlagebericht

Central Sierra Nevada

Sierra Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Lingering instability continues to be possible on weak snow that exists below our recent storm snow.  These problems could continue to exist in sheltered terrain near and below treeline.  Rapid warming today with sunny conditions will also cause snow to slide downhill on sun exposed slopes.  Monitor conditions while traveling in the backcountry and change plans if you see signs of instability. 

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–2.5

    Multiple weak layers exist in the snowpack under the recent Sunday storm snow.  These layers of concern exist in near and below treeline areas on NW-N-NE aspects.  The layer of buried surface hoar and near surface facets are showing signs of gaining strength and adjusting to the new storm snow load with signs of instability decreasing.  With that said, unlike typical storm slab issues, these layers will take longer to adjust and gain strength.  These weak layers vary widely throughout the forecast region in weakness and location.  Human triggered avalanches large enough to bury or injure a backcountry user remain possible.

    Look for signs of instability while traveling in the backcountry:  recent avalanche activity, shooting cracks, whumpfing, or collapsing would all be signs of an active weak layer in your area.  Remote triggering and wide propagation are also possible with persistent slab avalanche problems.  Utilize good terrain management strategies with your group to limit or avoid your exposure to this avalanche problem.  

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Snow surfaces became wet yesterday in the late morning with widespread roller balls on E-SE-S-SW-W aspects.  Warmer temperatures forecasted for today with decreased winds will further wet loose instabilities.  Many of these issues will be in the form of roller balls and pinwheels with larger wet loose avalanches that involve more snow becoming possible.  Some of these instabilities could also spread over to the northerly aspects depending on the warming in your area. 

    Once the snow surface becomes wet, heavy, and/or sticky, it is time to move off of and away from any steep avalanche terrain.  Snow surface conditions in these areas could have thin surface crusts in the morning turning into wet heavy snow as rapid warming occurs.  

Avalanche Discussion

  • Numerous avalanches were reported from the recent Sunday Feb 5 storm. All avalanche activity was thought to have occurred on Sunday, both natural and human triggered.
  • Whumpfing, cracking, collapses, and unstable snowpack tests were reported on both Sunday and Monday.
  • The layer of surface hoar buried on Jan 29 varies widely by location in both crystal size and weakness.
  • Wet surface snow existed on E-SE-S-SW-W aspects up to at least 8500' yesterday.  Thin sun crusts are expected in some of these areas today.

Abgedeckte Regionen